阅读说明：本技术 适用于降低激光束在液体介质中的衰减的装置和方法 (Device and method for reducing attenuation of laser beam in liquid medium ) 是由 T·威斯曼 A·卡恰图罗夫 A·普瑞斯 于 2017-06-06 设计创作，主要内容包括：一种对用激光照射靶向区域进行最优化的方法,该方法包括选择并安装激光照射传输设备,或者是使用导波器或者是光纤类型的仪器；同样地,选择至少以下参数的其中之一：选择将要被传输到靶向区域的至少一个序列脉冲的总能量,和选择从发射端的终部到靶向区域的距离；然后,开始对靶向区域进行照射至少一个脉冲序列,这是通过使用足够的能量(E<Sup>i</Sup>)来产生第一激光脉冲从而在液体介质中形成水气泡来完成的；允许所形成的水气泡膨胀到足够的数量,从而替换介于发射端的终端和靶向区域之间的液体介质中的大部分；以及在选定的时间延迟(T<Sup>d</Sup>)足以形成水气泡到达其最优化的范围之后,产生第二激光脉冲(E<Sup>p</Sup>),第二激光脉冲通过所形成的水气泡传输到靶向区域。(A method of optimizing the irradiation of a target area with laser light, the method comprising selecting and installing a laser light transmission device, either using a waveguide or a fiber optic type instrument; likewise, select toOne of the following parameters is reduced: selecting a total energy of at least one sequence of pulses to be delivered to the target area, and selecting a distance from a terminus of the transmitting end to the target area; then, irradiation of the target region is started by at least one pulse sequence by using sufficient energy (E) i ) To generate a first laser pulse to form a water bubble in the liquid medium; allowing the formed water vapor bubble to expand to a sufficient amount to displace a substantial portion of the liquid medium between the terminus of the emitting end and the targeted area; and at a selected time delay (T) d ) Sufficient to form a water vapor bubble to its optimum range, a second laser pulse (E) is generated p ) The second laser pulse is delivered to the target area through the formed water bubble.)

1. A medical laser system for treating a targeted tissue portion with a laser beam, the targeted tissue portion being movable within a body cavity and in a liquid medium consisting essentially of water, the system comprising: laser means adapted to generate an output laser beam; an optical fiber adapted to direct the laser beam to the tissue portion, the optical fiber having a delivery end proximate to but spaced apart from a targeted tissue portion to be treated; and a controller for controlling the laser device and functioning to continue generating at least a series of first and second laser pulses, the first laser pulse and the second laser pulse being substantially along the same longitudinal axis, and wherein the first laser pulse has sufficient energy to form a vapor bubble in the liquid medium at the delivery end of the optical fiber, and wherein the second laser pulse is formed a predetermined time after the first laser pulse, the predetermined time being selected to allow the vapor bubble to be generated by the first laser pulse and to expand to a sufficient amount to displace a substantial portion of the liquid medium between the delivery end of the optical fiber and the targeted tissue portion, wherein the controller controls the actuation of the second laser pulse such that after the vapor bubble has reached its maximum extent and has begun to collapse, the second laser pulse may be delivered to the targeted tissue portion via a vapor bubble, wherein the constricted bubble holds the tissue portion substantially stationary while the second laser pulse is delivered to reduce recoil of the tissue portion.

2. A laser system for medical use for treating a targeted tissue portion with a laser beam, the tissue portion being in a liquid medium within a body cavity, the system comprising: a laser device adapted to generate a laser beam; an optical fiber having a delivery end for directing the laser beam to the targeted tissue portion; and a controller for controlling the laser device to continue generating at least a first and a second laser pulse, wherein the first laser pulse and the second laser pulse are substantially along the same longitudinal axis, and wherein the first laser pulse has sufficient energy to form a vapor bubble in the liquid medium at the delivery end of the optical fiber, and wherein the second laser pulse is formed a predetermined time after the first laser pulse, the predetermined time being selected to allow the vapor bubble to be generated by the first laser pulse and to expand to a sufficient amount to displace a substantial portion of the liquid medium between the delivery end of the optical fiber and the targeted tissue portion, wherein the controller controls the actuation of the second laser pulse such that after the vapor bubble has reached its maximum extent and has begun to collapse, the second laser pulse may be delivered to the targeted tissue portion via a vapor bubble, wherein the constricted bubble holds the tissue portion substantially stationary while the second laser pulse is delivered to reduce recoil of the tissue portion.

3. A method of treating a target tissue using a laser beam, the target tissue being moveable within a body lumen and in a liquid medium, the method comprising: providing laser means for generating a laser beam; providing an optical fiber having a delivery end for directing the laser beam to the target tissue; providing a controller that causes the laser device to generate one or more laser pulses substantially along the same longitudinal axis; the controller causes the laser device to provide a first laser pulse having sufficient energy to form a vapor bubble in the liquid medium at the delivery end of the optical fiber; the controller continues to cause the laser device to provide a second laser pulse having an activation time selected to allow a vapor bubble generated by the first laser pulse to expand to a sufficient amount to displace a substantial portion of the liquid medium between the delivery end of the optical fiber and the target tissue, the second pulse being delivered to the target tissue through the vapor bubble after the vapor bubble has reached its maximum extent and has begun to contract; and wherein the constricted bubble holds the targeted tissue substantially stationary while the second laser pulse is delivered to reduce recoil of the tissue portion.

4. A method of treating a target tissue using a laser beam, the target tissue being moveable within a body lumen and in a liquid medium, the method comprising: providing laser means for generating a laser beam; providing an optical fiber having a delivery end for directing the laser beam to the target tissue; providing a controller that causes the laser device to generate one or more laser pulses substantially along the same longitudinal axis; the controller causes the laser device to provide one or more laser pulses configured by the controller to have sufficient energy to form a vapor bubble in the liquid medium at the delivery end of the optical fiber; the one or more pulses are selected to allow the vapor bubble to expand to a sufficient amount to displace a substantial portion of the liquid medium between the delivery end of the optical fiber and the targeted tissue through which the one or more pulses are delivered after the vapor bubble has reached its maximum extent and has begun to contract; and wherein the deflated bubble holds the tissue portion substantially stationary as the one or more laser pulses are delivered, thereby reducing recoil of the targeted tissue.

5. The method of claim 4, wherein the one or more laser pulses are more than one pulse train, further comprising the controller steps of: a repetition frequency is selected for the transmission of the more than one pulse train.

6. The method of claim 4, further comprising: selecting, by the controller, at least one of the following parameters: selecting a total energy for one or more pulses to be delivered to the target tissue, and selecting a distance of the delivery end to the target tissue.

7. The method of claim 6, further comprising the steps of: measuring the actual energy irradiated by the laser device; comparing the actual measured energy with the total energy selected by the controller; and, if the results of the comparison confirm a difference between the actual measured energy and the selected total energy, the controller adjusts the energy for any subsequent pulse to achieve the selected energy delivered to the target tissue.

8. The method of claim 7, wherein the step of measuring the actual energy transmitted by the laser device is performed by a photodetector positioned in the optical path of the laser radiation.

9. The method of claim 7, wherein the step of the controller adjusting the energy is accomplished by a closed loop feedback loop that is selectively connectable to the controller.

10. The method of claim 6, wherein the step of selecting the distance of the transmission end to the target tissue comprises the further steps of: measuring said distance and selecting said measured distance.

11. The method of claim 4, wherein the targeted tissue may be a tissue, an organ or a stone already formed within the human body.

12. The method of claim 4, further comprising the step of selecting and installing on the laser device a type of optical fiber for irradiating the targeted tissue.

13. The method of claim 12, wherein the type of optical fiber comprises at least one of the following parameters: fiber diameter, fiber material, fiber numerical pore size, and shape of the distal transmission tip.

14. The method of claim 12, wherein the controller intermittently identifies a parameter associated with a type of optical fiber mounted to the laser device.

15. The method of claim 14, wherein the step of automatically identifying is accomplished by an RFID identification code mounted on the transmission device and on the waveguide or optical fiber.

16. The method of claim 12, wherein the controller indicates information related to the controller on a user interface if a fiber type is available for the selected treatment.

Technical Field

The present invention relates to a laser energy source, and to a method and apparatus for reducing attenuation of a laser beam through a liquid environment to a target tissue.

Background

Over the past two decades, treatment with laser devices has become a common form in the medical field. New laser technology and delivery systems, with low price and high quality laser delivery systems, are only a new driver. Some laser treatments are performed in a direct manner in free, developed space, for example, on the surface of the skin. However, some treatments require support from a transmission system, for example, transmitting a laser beam through an optical fiber or light guide. In certain embodiments of the above-described treatments, the signs of the treatment site are a gaseous environment (e.g., in a laparoscopic procedure controlled by insufflation gas).

However, some laser treatments are performed in a liquid environment, such as the fragmentation of kidney stones or the elimination of prosthetic hyperplasia, to mention just two. From an optical perspective, among other things, the efficiency of energy transfer from a laser beam to targeted tissue depends on the medium through which the laser beam is transferred from its light source to the targeted tissue. In general, liquid media tend to absorb more light and scatter light than gaseous media. The liquid medium may include water forming a portion thereof, which is known to be capable of absorbing light energy, typically, strongly, particularly in the wavelengths of infrared light.

Infrared lasers, such as thulium, holmium, erbium, carbon dioxide, or the like, are commonly used in general surgical, orthopedic, urological procedures. Since most of these procedures are performed in vivo, it is anticipated that a portion, or even a substantial portion, of the laser energy emitted from the output end of the light guide or fiber will be absorbed by the liquid medium before reaching the targeted tissue.

However, as taught in U.S. patent No. 5,321,715 (the' 715 patent), in some cases, the laser energy emitted through the liquid medium toward the target tissue will be absorbed, but such absorption is less than expected. This is due to the so-called "morse effect", in which a first part of the emitted energy is absorbed by the liquid and forms bubbles in the liquid medium, so that the remaining energy can pass through a less confined or absorbing gas/vapour medium, characterized by a lower light attenuation.

The' 715 patent describes a pulse format for enhancing the laser energy that will reach the targeted tissue. According to what is described therein, a first short and low energy initial pulse is emitted in order to generate a bubble, followed by a higher energy treatment pulse. The second treatment pulse experiences a lower rate of absorption as it passes through the generated and newly formed bubbles due to the presence of the bubbles (and lack of liquid). Moreover, the' 715 patent teaches that the energy of the initial pulse of the first bubble will be sufficient to initiate the formation of the water vapor bubble. Thus, a bubble will then be created which will then replace most of the liquid medium located between the line end and the target tissue.

The time period between the first and second pulses is calculable and can be determined on the basis of the expected expansion rate of the bubble and the actual distance from the fiber end or light guide end to the target tissue. Once the bubble is generated, certain factors arise that control its spontaneous expansion, and after that a second pulse occurs, according to the teachings of the' 715 patent, prior to the bubble bursting. Van Leeuwen teaches us in the prior art ("Non-contact Tissue amplification by Holdium: YSGGLaser Pulses in Blood," Lasers in Surgery and Medicine, Vol. 11 1991): the diameter of the bubble extends from about 1mm in 100 microseconds to about 2mm in 200 microseconds. Thus, the' 715 patent teaches a time period of less than 200 microseconds between the initial pulse of bubbles and the subsequent treatment pulse.

According to the' 715 patent, the initial pulse of the bubble is preferably less than 50 microseconds, and more preferably less than 30 microseconds. In one embodiment described in the' 715 patent, where a holmium treatment laser beam is provided and a 0.5mm fiber diameter is used, the initial pulse of the bubble will be at least 0.02 joules-energy requiring a 2.1 micron laser beam emitted through the fiber end to boil the water. According to this embodiment, the consumption of the initial pulse of bubbles is 2% of the treatment pulse of 1 joule.

5,632,739 teaches that the delay between the initial pulse and the treatment pulse of a bubble is carefully determined so that a second pulse can be emitted when the size of the bubble and the corresponding amount of liquid displaced reach its maximum range.

However, it is currently the case that a large portion of the pulse energy is still absorbed by water or biological fluid during its passage to the targeted tissue. Non-optimal fiber tip-to-target tissue distances can greatly affect treatment efficiency and can actually reduce treatment efficacy.

However, the prior art fails to provide any method as to how to control and optimize the inflation phase of the bubble, i.e. to define, adjust and optimize the first initial pulse, which is emitted by the laser system, as a function of a specific set of parameters defining a specific working envelope-total pulse energy for treatment selected by the user, the repetition frequency of the treatment pulses, the fiber diameter and working distance, the distance from the fiber end or waveguide to the targeted tissue and the laser type. In addition, the prior art fails to provide an optimized method of determining the delay between the initial pulse and the treatment pulse. One aspect of the present invention addresses the above-mentioned deficiencies in the prior art.

Disclosure of Invention

In one aspect, an optimized irradiation method for targeting a target with laser radiation, wherein the laser radiation is associated with a laser radiation delivery device and the laser radiation is delivered to the target by way of a waveguide or optical fiber, each of the waveguide or optical fiber having a distal delivery tip, wherein the distal delivery tip is spaced from the target, wherein a spacing between the distal delivery tip of the waveguide and the target is occupied by a liquid medium, and wherein the laser radiation is delivered along an optical path of at least one of the chains of laser pulses of at least a wavelength that is at least partially absorbed by the liquid mediumAt least one pulse train has a first laser pulse and a second laser pulse. The method comprises the following steps: selecting and installing the type of laser radiation delivery device, waveguide or optical fiber to be used to irradiate the target; then, at least the following parameters are selected: selecting a total energy of at least one of the pulse trains to be delivered to the target and selecting a distance from the distal delivery tip to the target; the method still further includes providing a controller that controls the laser radiation delivery device and performs the steps of selecting a total energy delivered by the laser radiation delivery device and selecting a distance from the distal delivery tip to the target object; the method further comprises initiating irradiation of the target, adapted to generate at least one pulse train of first laser pulses having sufficient energy (E)ⁱ) So that vapor bubbles can form in the liquid medium at the distal transport end; allowing the formed vapor bubble to expand to a sufficient amount to displace a substantial portion of the liquid medium between the distal transmission tip and the target; then, a delay time (T) is selected to be sufficient to form the vapor bubbles and optimize them^d) Thereafter, a second laser pulse (E) is formed^p) The second laser pulse is delivered to the target through the formed vapor bubble, thereby minimizing the amount of laser radiation absorbed by the liquid medium and maximizing the amount of laser radiation that reaches the target. The controller may further include a memory containing a lookup table including a plurality of parameters Eⁱ、E^pAnd T^dAnd wherein the steps of selecting a waveguide or fiber type, selecting a total energy to be used for radiation, and selecting a distance from the distal transmission end to the target cause the controller to expedite the search of the table to be Eⁱ、E^pAnd T^dSelects the corresponding parameter and causes the transmitting device to generate and transmit a signal having a value of Eⁱ、E^pAnd T^dLaser radiation of selected parameters.

In another aspect, Eⁱ/E^pMay be from 10:1 to 1:10, at least one of the pulse trainsOne of which includes two pulses or more than two pulses. At least one of the pulse trains may have more than one pulse train and the step of selecting may further comprise selecting a repetition frequency for transmission of more than one pulse train.

From yet another aspect, the method further comprises the steps of: measuring the actual energy irradiated by the laser; comparing the actual measured irradiation energy with the selected total energy; and, if the comparison results confirm a difference between the actual measured energy and the selected total energy, a determination of one or more selected parameters of any subsequent pulse train is required to obtain the selected energy for delivery to the target. The target may be a tissue, organ or already formed stone within the human body.

In a further aspect, the search table includes one or more databases containing Eⁱ、E^pAnd T^dOptimizing values for a large number of waveguide or fiber types and distances from the remote delivery tip to the target, and the step of selecting a waveguide or fiber type results in the controller expediting the search of the table to determine Eⁱ、E^pAnd T^dIs determined.

Viewed from a still further aspect, the type of waveguide and optical fiber includes at least one of the following parameters: fiber diameter, fiber material, fiber numerical aperture and profile of the distal transmission tip.

In one aspect, the step of selecting a distance from the distal transmission tip to the target object comprises further measuring the distance and selecting the measured distance. Further, the step of measuring the actual energy transmitted by the laser is performed by a photodetector positioned in the optical path of the laser radiation. The step of adjusting one or more parameters is accomplished by a closed loop feedback loop that may be selectively coupled to a programmable controller.

Viewed from another aspect, the step of selecting the type of waveguide or the type of optical fiber comprises the further step of mounting the waveguide or optical fiber to a transmission device, and wherein the device can automatically identify the parameters of the waveguide or optical fiber. Further, the step of automatically identifying is accomplished by an identification code mounted on the transmission device and on the waveguide or optical fiber.

Viewed from a still further aspect, the programmable controller indicates information on the user interface relating to the programmable controller whether or not the waveguide or fiber type is appropriate for the selected one or more parameters. Further, at least one pulse train comprises one or more of the following parameters: eⁱAnd more than one E^p。

In another aspect, the controller controls the delivery device of the laser radiation and performs the steps of selecting a total energy delivered by the laser radiation delivery device and selecting a distance from the distal delivery tip to the target based on the type of waveguide or optical fiber mounted on the delivery device.

In one aspect, a method of irradiating a target with laser radiation, wherein the radiation is delivered to the target by a conductor having a delivery end, and wherein the delivery end is spaced apart from the target, and wherein the delivery end of the waveguide is at a distance from the target member occupied by a liquid medium, and wherein the laser radiation has a wavelength that is absorbed in the liquid medium, the method comprising the steps of: generating a first laser pulse having sufficient energy to form a vapor bubble in the liquid medium at the transmission end of the waveguide; and generating a second laser pulse within a predetermined time after the first laser pulse, the predetermined time being selected to allow the vapor bubble to expand to a sufficient amount to displace a substantial portion of the liquid medium between the delivery end of the waveguide and the target object such that the second laser pulse can be delivered through the vapor bubble to the target object to minimize the amount of laser radiation absorbed by the liquid medium and maximize the laser radiation reaching the target object.

In yet another aspect, a laser system for medical use for treating tissue having a laser beam, wherein the tissue is in a liquid medium consisting essentially of water, the system comprising: the solid state gain medium produces an output wavelength between 1.0 and 10.6 microns; a flash lamp for exciting the gain medium to generate a laser beam; an optical fiber adapted to direct a laser beam from the gain medium to a target, the optical fiber having a transmission end in close proximity to but spaced apart from the target to be treated; and a controller for controlling the flash lamp and functioning to continue generating the series of first and second laser pulses, wherein each of said first laser pulses has sufficient energy to form a vapor bubble in the liquid medium at the delivery end of the optical fiber, and wherein each of said second laser pulses is formed a predetermined time after the first laser pulse, the predetermined time is selected to allow a vapor bubble to be generated by the first laser pulse, and may expand to a sufficient amount to displace a substantial portion of the liquid medium between the delivery end of the optical fiber and the target, such that the second laser pulse may be delivered to the target via a vapor bubble, thereby minimizing the amount of laser radiation absorbed by the liquid medium and maximizing the laser radiation that reaches the target.

Drawings

Fig. 1A, 1B and 1C illustrate the difference between the normal pulse (1C) and the double pulse (1A and 1B) in principle.

Figure 2 illustrates diagrammatically an embodiment of the apparatus according to the invention.

Fig. 3A and 3B are flow charts illustrating the operation of the apparatus of the present invention of fig. 2.

Fig. 4 is a numerical array showing the relationship between parameters for a 200 micron fiber.

Fig. 5A and 5B and fig. 6A and 6B illustrate the optimized distance with respect to output power and fiber size, respectively.

Fig. 7 is a graph illustrating the relationship between bubble length and output power.

Fig. 8,9 and 10 illustrate schematic diagrams of various embodiments of holmium and thulium laser cavities according to the present invention.

FIG. 11A illustrates an experimentally confirmed example of the operation demonstrated by the apparatus of the present invention.

FIGS. 11B through 11G illustrate experimental results of the operation of the apparatus of FIG. 11A.

Embodiments also include optimization of treatment parameters that shape and adjust the laser pulses to provide more efficient laser-tissue interaction. This may involve optimization of the pulse energy, the level of pulse energy, the number of pulses, the type and size of fiber used, and the distance between the fiber end and the targeted tissue. Two pulses may be used so that the second pulse may cross into the bubble formed by the first part of the pulse. Thus, the timing of the second pulse and any delay between the first pulse and the second pulse may provide further optimization benefits. Furthermore, the optimization may be to work in a "closed loop" model, whereby various controllable parameters may be controlled and varied in the process to provide the most efficient treatment.